Photography.



55 negative.

FRANK WORDSWORTH DONISTHORPE, OF BATH, ENGLAND.

PHOTOGRAPHY.

Specification of Letters Patent.

Patented m 25, 1909.

Application filed May 22, 1908. Serial No. 434,376.

To all whom it may concern? Be it known that I, FRANK WoRnswoRTn DONISTHORPE, entleman, a subject of the King of-Great %3ritain, residing at Hohen- 5 fels, Combe Down,- Bath, England, have invented new and useful Improvements in Photography, of-which the following is a specification. I

The object of this invention is by anim- '10 proved method of rendering portions of a photographic negative uns'aturable by aqueous'dyes, to provide a plate'which shall be capable of bein 1 used as a hydrotype print ing plate for co or photography or as a colored transparency.

According to this invention I load or charge with mineral or pigmentary matter the more opaque parts of an ordinary gelatin emulsion negative or other similar negative having a gelatin basis, whether on glass, celluloid or other su ort, and thus render theseparts unsaturaiil e by aqueous dyes or ,iluids, this resistance to the entry of aqueous fluids being proportionate to the amount of light that has acted" on the different parts, and after this treatment the negative is soaked in the aqueous" dye or solution.

Provided that the solution" or solutions used to transform the negative into a hydrotype printing surface, can fulfil the essential condition of so reactingwith the silver of the negative as to cause the deposition of a pigmentary material, there may be a wide choice in the matter ofsolutions or baths, so it is in] ossible to specify every individual solution tliat can be used, but I will particularize the following not only as examples but also as all'ording specific instructions for the practical. working of the process. The pro- 40 portions of the ingredients here given must be considered as approximate, as they may be varied considerablv without materially all'ecting the result.

Example 1 lnnnerse the negative inA for ten minutes, and follow with B for the same period. In bath A a deposit of uranium is made on the By depositing the negative in bath B, a deposit of iron is obtained.

.is blackened.

bath or printing solution.

- Example 2. 7 A. Lcadnitrate.-' .4 parts.

Potassium ferricyanid -6 parts. Acetic acid 2 parts. G1y'cerin l ..1 part. VVater-HU -100 parts.

I Immerse in A for ten minutes and followwith B for same period. In bath A the image is bleached, while in bath B the image Exampled.

Vanadium chlorid -2-parts. Potassium ferricya'ni d 2 parts. Ferric chlorid. 1 part. Glycerin- -1' part. Ferric oxalate- --1 part.

Saturated solution of oxalic acid 10() parts. -900 parts.

So far as my present eicperience takes me, I prefer the bath last mentioned. The negative is allowed to remain in the bath until the action is fully com leted; in

' most cases this should be in somet ring over ten minutes, but prolonged action, as for ex- 4 ample all night, usually does no harm. The negative is then washed in cold water for a few minutes, and transferred into the dye.

If the printing is rot to be performed at once the negative may be dried and stored away after washing, and

'at any subsequent period it may, he charged with dye and used as a hydrotype printing plate.

The prepared or treated negatives should be kept in the dye bath or printing solution for about ten minutes. and then rinsed for about a minute in cold water. ln order to print from a negative thus saturated with the dye or the printing solution, it is brought into contact with gelz'itin coated paper, which has been previously soaked in cold water for about a minute. The negative and paper may be brought into contact under Water, or immediately after they have been taken out of the water. They are now squeegeed together and left in contact for about ten \minutes. It is convenient to cover the negative and )aper with a damp cloth at this stage and lay a plate ol glass over, :50 as to keep all compact and moist. The ten minutes having elapsed the gelatined paper is stripped from the .icgatiw,

lit)

and the, paper now bears a positive impression in dye from the negatlve. The negative may then be redyed and used over and over again, the redyeing only taking about three minutes. Tlus latter part of the process, from the. time the negative-has been ,re-'

moved from the dye or printing so'lutionis exactly the same as in the case of other hydrotype printing methods, as for example printing fromthe positive transparencies in Working the pinatype process.

One important use of'my invention Will be 'for three color work, by bringing the gelatinized paper into contact with the three stainednegatives in turn, the whole making the complete color picture, just as the effect is obtained in the pinatype process from ducer, and a reducer compounded of potasslum ferricyanid one part, carbonate of soda crystals six parts and Water-forty parts.

In order to make a three color transpar-.

ency by this method, one'of the negatives should be taken reversed in the camera through the back of the plate and the second should betaken direct or unreversed, while the third should be on film.. The two pictures taken on the plates .are now mountedface to face, with the picture on film between them.

What I claim is 1. The method herein described which consists in renderingiportions of a photographic negative unsaturable by aqueous dyes by loading the more opaque parts of the negative W1th pigmentary matter and then soaking the negative in an aqueous dye.

2. The method herein describedwhlch con- 'sists inrendering portions-of aphotographic negativeunsaturable by aqueous dyes by loading the more opaque parts of the negative with pigmentary matter, washing in cold water and then soaking the negative in an aqueous dye.

3. The method herein described which consists in rendering portions of a photographic negative unsaturable by aqueous dyes by loading the more opaque parts of the negative with pigmentary matter, soaking the negative in anaqueous dye and then bringing the negative into contact 'with a gelatin surface.

. 4. A-printing plate having its more opaque parts loaded with pigmentar matter and which has then been soaked in an aqueous dye.

' FRANK WORDSWORTII DOXISTllORll-l.

Witnesses:

'H. D. JAMESON,

B. WILLIAMS. 

